As the US government pushed to intern Japanese-Americans in prison camps during the war, for fear that they might constitute a ‘fifth column’ within the country, Hirabayashi was one of a handful of citizens who refused to surrender to such a fate. In the landmark 1943 Supreme Court case Hirabayashi vs United States, which he lost despite backing from the American Civil Liberties Union (ACLU), he argued that he should not be punished without having actually done anything wrong.

After the Second World War, Hirabayashi became a noted sociologist and spent many years at Canada’s University of Alberta. In the 1980s, he was able to secure the overturning of his wartime conviction for curfew violation, a development that he said was a vindication of his determination to fight on despite knowing that the odds were stacked against him.